Shock absorber



Sept. 21,1926. 1,600,544

- J. HOFMANN SHOCK ABSORBER Filed Feb. 6, 1923 Z f' T5 fN ITT ill)

Fatenteu `wept. 21, 1926.

the hydraulic type,

Application lcd February 'riads PATENT orricll.V

JOSEF `IHOFMANN, OF BAUMAROCHE; SWITZERLAND.

SHOCK ABSORBER,

i I My invention relates to shock absorbers of in which the body spi-ing is free to operate from its normal position liiiit'which will retard the movement of the spring back'into its normal position.

action of a cam on a pis mally urged against when the cam is moving from Speeilically, the

invention includes ton-like member norsaid cam by a -spring the the piston.

The return ot' the cani to normal position is retarded, either directlyor indirectly,

the spring.

`illhatever the construction and assemblage t these parts. there shall be an actuating member movingr a power member and angulai'ly' displaced therefrom, mechanism arranged with nouer mechanism on and for resistance to movement in dii-ceti the actuating member to member to move the bi'a ior free ie other direction which peeds.

and a braking respectto the movement in one is effective at all 'ln operation, such an arrangement causes varying amplitude, and

operate the poiver king member with upon the return t the parts to normal position converts the constant resistance ol" the into a decreasing resistance "which is effective at all speedsA `lieferringl, to the drawings, in which like arts are similarly designated- Figure l. is

Fie".

comprises a body mein stantiaily ilat on 'one (l sion n of the vehicle.

Fig. 2-is a vertical sect is a sction on lin Fi, 3 Fi l iiiv shook Slil. t' sii-TuningY it against tno Fo i fastening this member,

screvil, and at t l 9 and threaded 'for receiving cylinder li).

`t having' a cylini'l dlc square portion rival bearing portion 1S a lie bottom is eyli braking member a side elevation of my shock absorber attached to a motor vehicle.

ion on line 2--2,

is .n.t-ransverse section on line absorber, as shown in Figs. L4, bei or casting.: 5, sub

for the purpose body traine extenr the purpose ot it is provided with pass. the securing,y

top, closeddhy a ndrical alt and holding a ssirgy through the body iiiembei' is a rical vsvi'iall end ll., a

a larger cylinnd a square outer 6, 1923." Serial No. 617,303. f f l.

endk 14g, the latter for the reception of an actuating lever 15. i

This lever 15 is preferably split at its end, as at 16, and a tighteningbolt 17 passed through the split end. The lever 15 is connected by a rod 18, Whose length is adjustable to accommodate ditlerent dimensions of vehicles, to a running gear element 4of the vehicle.. The lower endl of this rod is pivoted at 19 for connection to arunning gear member. hereshown asa plate 20 lying beneath the body spring b of the vehicle.

lVithin the body vmember 5 on the square portion Vl2 ot the shaft l mount a power' member or cam 2l having a grub screw 22 smaller than the screw 8, so thatvit can be inserted through the filling opening. The cani is preferably provided with an antifriction roller 23. This roller, or the cam proper, if the roller is omitted, rests on the closed end of a hollow piston 24 litting the cylinder 10 that is provided through the closed end with passages 25. The piston is open at its opposite end,'ivhieh is interiorly threaded for the reception ot' a partition 26, also provided with ports 27.

This partition divides the assemblage of body member and' cylinder into tivo fluid chainliers one above and the other below it, which chambers Vary in capacity in accordance with the vertical position of the partition and piston.

Resting,i on top ot this partition is a plate 28 provided. with poi-ts 29, and this plate is held seated on the partition by a heavy spring,r 30. A bead 3l on the lower face ot theplate 28 prevents this plate from stieking,` to the partition 'or closing the 'ports 27 and 29. i

Beneath the partition is a spi-ing 32 lighter than spring 30, and Whose function is to urge the hollow perforated piston'toward; the cani 2l. y

The plate 28 has a. tubular stern 34 passing through the partition 2G and terminating' below the partition in a flange 35 4provided with a retaining,r groove. 3G Jfor a light spring 37 that'supljiorts a one way valve38 against the under tace of the partition and closes the ports 27; Thisvalve controls the 4passage ot liquid troni the chamber above the iai-titiou to the chamber below it.

"lhe hollow strani 34 is provided with holes fifi that are controlled by the partition 26 4throng-li which the tubular valve Mslides,

and constitutes a throttling valvecontroiling the passage of liquid from the chamber below the partition to the chamber above it.

The operation is as follows:

When the vehicle spring is stressed, either by the vehicle spring and axle raised or lowered from normal position by reason 'of shock or ruts in the road, or when the vehicle body suddenly rises or lowers with respect to the vehicle axle, rod 18- is moved to move lever l5 and cause relative 'rotation'o'fcam 21 and body member; that is to say, the cam 21 and its roller 23 are displaced to one side or the otherl of the position shovvny in Fig. 3.

This permits the hollow piston 24 to rise inmaintained contact with thel cam under the influence' of its spring 32. (lil will then be freely displaced from the body member 5, through holes 25 to the interior of the piston, thence through holes 29 in plate 28 and holes 27 in partition 26 past the valve 38, which is urged to close the holes 27 by chamber below the partition 26 and the chamber `above it and the 'pieton is through tubular stem' orfthrottlevalve 34 which ie raised by the pressure of the oil in said at its upper end on the plate 28. This' plate is underl the pressure of the strong spring 30, and by reason ofthe small crossfsectenel area of'tube 34 there must be a considerable pressure to lift `the plate 28 es it rises with tube 24 to open more or lees the openings or ports 39 vthat throttle the passage of oil therethrough to the-'space above the partition.

Oil after passing through the valve porte v39@ is free to .pass around the plate and through the plate holes 29 into the space within the piston above the partition 26 and thence throu h the holee'25 in the top of the piston into t e body member 5.

In this manner the return movement or rebound is efficiently checked and slowed down, excessive oscillations of the car body are prevented, and the oscillating parts are h quickly returned to normal position, by rea! Son ofthe decreasing,r resistance due/to the rate of change of the effective leverage oi the power member cam) and the actuating lever in relation to the movement of the liquid throttling members, which relation is f a decreasing ratio.

recette lt will be noted 'that the partition. is in threaded connection. with the piste '1, by rean son of which it maybe adjusted up or down. to varythepressur'e Iofthe heavy springl 3G that controls-the tubular valve 3ft, and 'thus j the shock absorber may, be adjusted for norN mal loads off cars or' di'erent types maires.

1. A shock absorber having an actuating ineinberand a power member angularly displaced from one another, a braking memberheving reemovement in one direction when said power member is moved in either direc# tion from normal positions, means to prof duceel constant resistance to movement. ii?. the othcrdireetion and effective at all speeds, and a device to transmit the movement of the power 'member upon said mechanism with varying amplitude and convert the con stanti resistance of said inea-ns into a decreasing resistance effective at all upon movement of the parte to normal position 2.7l'n a hydraulic shock Aabsorbe cylindeiga hollow piston thereiii vented int/o the cylinder, a partition stationery in the piston having one Way free flow valve-conirolled openings, a throttle valve controllingI ow to theopposite side of seid partition, e, spring between said iston and votre end means to operate sai piston;

3. ln a hydraulic shock abeorber, e@

cylinder, a hollow piston thereinmeans to' operate the lpiston in one direction, separate means to operate the piston in the opposite direction, said pieton having commimicetion at both oits ends with said cylinder, e par.

tition stationary in 'said piston one-wey :treo

How valve-controlled paseeges from one side of said partition tothe other, 'a throttie veive controlling' reverse ilovv from one side or seid partition to the other and e. spring the movement ci said throttle valve.

4e In a hydraulic shock absorber, a cyliir v der, a hollow piston therein, means to operate the piston in one direction, "seperate means to operate the piston in en opposite direction, the interioro'l said piston herring maintained@communication with both enf-fi of said cylinder, a. partition in the piston having Oneway free-flow valvecontrolied passages from one side to the other, throttle valve controlling the lovv of liquid in the opposite direction past seid partition,

and a' spring controlling said valve, seid partition being adjustable to adjust the ten sion of said spring.

f 5. In a hydraulic shock absorber, a cylin-- der, a hollow piston therein having; main tained communication at both ends with said cylinder, a cam to operate the piston. in one direction, a spring to operate said pieton in the opposite direction, a partition in said piston having ports therethrough, a springurged valve beneath said partition control` piston.

ports,` a ported plate above said a tubular valve connected to sai movable therewith vand a spring one end of said ling said partition, late and tween said plate and 6. In a hydraulic shock absorber, a cylinder, a hollow piston, a ported partition sta tionarily mounted the'rein y dividing the piston and c linderinto two chambers and movable witi said piston, 4a spring-closed valve controlling the flow one-way from one chamber to the other, a valve controlling the passage of liquid in an opposite direction, a

loading said valve and bodily mova le with said piston, means arranged for connection to av vehicle memberfto move said` pieton in one direction and a spring to move said listonl in an opposite direction.

7. In a hydraulic shock absorber, Aa cylinder, a hollow piston therein, a. ported partition in the piston dividing the piston and cylinder into two chambers, aspring-closed valve controlling the flow one way `from vone i .chamberto the other, a valve controlling the flow of liquid in an opposite direction., a; spring loading lthe-latter valve` a rocking cam operated from a movable ineiiibc'r of the vehicle to move said 4piston in one and a spring to urge the. piston toward said l0 cam.

8. In a h cylinder, a'

draulic shock absorber, a main llow piston therein consisting opposite side of said partition,

ymoved iii either direction position.

direction. ln testimony that I claim the foregoings 00* 9. In a hydraulic shock absorber, a niain "4,5

cylinder a hollow piston therein consisting of a cylinder having a hood at one end and vented therethrough to the main cylinder and open at the other end, a partition stationary in the hollow piston treeflow openings therethrough, means to adjust the partition` a throttle valve controlling flow through said openings to the a spring between said piston and movement .of the piston when said device from its normal as my invention I have signed my naine hereto.

JOSEF HOFMANN.

hoo-,d at one end and j at the other end, a partition. sta- 35 having Oneway, 50

valve and a cani dee 55 vice operating on the piston head to allow 

